Study: High xylitol levels in blood possibly linked to increased cardiovascular risk

The team reports that individuals with the highest measured xylitol levels in the blood showed a 57 percent higher risk of a serious cardiovascular event over a follow-up period of six years in the CLSA cohort than individuals with the lowest levels. According to the information provided, the risk estimate was adjusted for known influencing factors such as age, sex, smoking status, cholesterol levels, diabetes, and high blood pressure. This means that lifestyle and pre-existing conditions as statistical explanations cannot be ruled out, but the association remains even after this adjustment.

What do the numbers show?

The serious cardiovascular events are defined according to standard definition as including, among other things, heart attack, stroke, and cardiovascular-related death. For the analysis, the study group evaluated samples and longitudinal data from a large Canadian cohort, in which blood samples were biobanked over years and linked with clinical endpoints. Data from the EPIC cohort, the European Prospective Investigation into Cancer, were also included in the evaluation.

Witkowski and his co-authors see indications in the results that the body can produce xylitol itself and that the concentration measured in the blood does not solely reflect what someone ingests through sweeteners. This makes it difficult to derive simple recommendations such as 'eat less xylitol' directly from the data. The researchers also emphasize that this is an observational study: it can show associations but cannot prove a causal effect.

At the time of the congress announcement, the study had not yet been published in a specialist journal. This means that the external scientific peer review, which typically examines the methodological quality, statistical robustness, and transferability of the results, is still lacking. Only after such a peer-review process can it be estimated how robust the association actually is.

What the study cannot prove

The European Society of Cardiology (ESC) regularly presents new studies at its annual congresses before they appear in specialist journals. Such advance presentations are common in the professional world but regularly face critical questions, because central methodological details are often only fully disclosed in the later publication. The ESC itself also recommends not overestimating such results as long as they have not been externally peer-reviewed.

For proper interpretation, it is important that the xylitol levels measured in the blood cannot be equated directly with the usual intake through food. How much xylitol someone consumes through chewing gum or baked goods depends heavily on the product, the amount consumed, and individual metabolic factors. A simple recommendation of 'more or less xylitol' therefore cannot be derived from the available data.

What does this mean for consumers?

The study joins a growing body of work examining individual sweeteners and their possible metabolic effects. Xylitol was previously known mainly for its effect on blood sugar and because of a warning from the U.S. Food and Drug Administration regarding poisoning risks in dogs. Should the new results be confirmed in further review, a more detailed discussion about the tolerability of the substance for humans would also be necessary.

For consumers, the researchers advise not to take the new data as a reason for radical dietary changes for the time being. At the same time, it would be sensible to generally question the consumption of heavily sweetened products, including those with sugar substitutes, as long as it remains unclear which long-term effects are associated with high intake levels.